The present invention relates to a method of producing in a high yield cells of Pseudomonas bacteria having a high nitrile hydratase activity.
In recent years, the technology of immobilized enzymes or microorganisms has developed rapidly, resulting in increasing attempts to utilize microorganisms and enzymes as they are or in an immobilized state as catalysts for various single or complex chemical reactions.
Nitrile hydratase has been found by Hideaki Yamada, one of the present inventors, et al. as an enzyme capable of hydrating nitriles to produce the corresponding amides. (Reference: Agric. Biol. Chem. 46 1165 (1982)) As one example of the utilization of this enzyme, a method for preparation of acrylamide from acrylonitrile in the presence of bacteria having nitrile hydratase has been proposed. (References: Japanese Patent Laid-Open Pub. No. 86093/1983 (Japanese Patent Appln. No. 184688/1981) and Agric. Biol. Chem. 46 1183 (1982))
Under these circumstances, a method that can ensure the production of cells of Pseudomonas bacteria having a high nitrile hydratase activity in a high yield would be remarkably beneficial.
From the foregoing point of view, some of us have proposed a method in Japanese Patent Appln. No. 1997/1983. The method for cultivation of Pseudomonas bacteria disclosed in this Japanese patent application comprises adding cysteine and/or cystin to a culture medium in the preparation of cells of bacteria having nitrile hydratase activity by cultivating under nitrile hydratase-inducing conditions Pseudomonas bacteria capable of producing nitrile hydratase.